In fabricating semiconductor structures, the source/drain resistance is reduced by forming a layer of a refractory metal silicide. In particular, a refractory metal is deposited and then subjected to elevated temperatures, thereby reacting with underlying silicon to form what is commonly referred to as a "silicide". Silicides are well known in the art and provide dependable silicon contacts as well as low ohmic resistance.
Silicides are commonly used to reduce the source/drain resistance between adjacent gate structures. However, as device dimensions shrink, so does the spacing between adjacent gate structures. The available space for silicide formation shrinks faster than the ground rules for gate-to-gate spacing due to the finite width of the gate spacers. The shrinking lateral dimensions increase the resistance of any device that uses the source/drain as a conduction path. The formation of silicide in narrow spaces between gates may also be more difficult, leading to an elevated and variable resistance in these regions.